Exception in loadValue where this is no result

Support
#1

I am using the following mechanism as per the user guide. It works when the query returns a result but get an exception when there is no result returned.

                            totalHours = dataManager.loadValue(
                                "select sum(e.resourceHoursRequired) from erp$PlanOrderContinuousProd e " +
                                        "where e.prodDate = :prodDate and e.operation.id = :opsId group by e.prodDate", BigDecimal.class)
                                .parameter("prodDate", planDate)
                                .parameter("opsId", operation.getId())
                                .one();

The exception is as follows:

java.lang.IllegalStateException: No results
at com.haulmont.cuba.core.global.FluentValueLoader.one(FluentValueLoader.java:112)

Is there any straightforward way we can get value 0 instead of this exception?

#2

Hi,

you can use optional() (see API docs), which will return you a java.util.Optional, which you can easily check for existence. With orElse() - API docs you can return the value or a default value.

Bye
Mario

#3

Thanks Mario.
So, the code will look like as follows:

totalHours = dataManager.loadValue(
                                "select sum(e.resourceHoursRequired) from erp$PlanOrderContinuousProd e " +
                                        "where e.prodDate = :prodDate and e.operation.id = :opsId group by e.prodDate", BigDecimal.class)
                                .parameter("prodDate", planDate)
                                .parameter("opsId", operation.getId())
                                .optional().orElse(BigDecimal.ZERO);

I have used following alternative codes:

Query query1 = em.createQuery("select COALESCE(sum(e.resourceHoursRequired),0) " +
                                "from erp$PlanOrderContinuousProd e " +
                                "where e.prodDate = :prodDate and e.operation.id = :opsId group by e.prodDate")
                                .setParameter("prodDate", planDate)
                                .setParameter("opsId", operation.getId());

If both are used in server side, is there any reason one should be picked as a preference between the above two when one using DataManager and other use em?

#4

There are various differences between DM and EM. It depends on what you need.

See: DataManager vs. EntityManager - CUBA Platform. Developer’s Manual

Bye
Mario

#5

Thanks. I came across this comparison ealier but was interested in exchanging thoughts. can we say EntityManager will perform better when we do not need security restriction as DataManager checks by default?

#6

Hi Mortoza,

The difference in performance is absolutely negligible, so use DataManager if you don’t need transactional operations and persistence context.

#7

Thanks Konstantin for the suggestion. So you mean even in server side, one should prefer use of DataManager when there is no transnational operation and persistence context used. I know you have a very deep knowledge of this technical aspects, will do so without any doubt. Just curious, if there is any reason of recommending use of DataManager as preferred one?